> "It’s simply too subjective (teenagers will find almost any nudity sexual, no matter its context). How does anyone decide if any nudity is age-appropriate? Especially at scale."
OK (blog author) has made the case that one cannot decide, the government has gone with "ban by default". If you (blog author) object to that, can you make a case why that's bad? You wrote "apart from 'think of the children' being a classic call to censorship" so you've closed off that route for your objection which may have been a strong one.
If you work then you have given your employer proof of ID for things like showing your right to work in the UK, getting a paycheck, or a criminal record check; so the principle of an employee proving their age seems out of scope for you to object to - at least you haven't made a case that people need to be able to work anonymously. [Although the method of proving one's age is up for argument, it's not this argument].
It boils down to: if you can't decide, do you allow by default or block by default? Government has gone for default-block, blog author seems to be taking the position that default-allow is better but has not made a case why.
By comparison we tried that with digital security - for years computer systems were default-allow and it caused a lot of problems and we've had to reengineer them to have firewalls, ports closed, seperated user accounts, minimal user account permissions, minimal data-execute permissions, minimal employee access to company systems, minimal access from one app into another's data, then in each case grant-as-necessary with proof of identity and audit logging that it happened. Result? Reduced problems, reduced hacks, reduced crime, limited blast radius of mistakes.
It used to be that we made any product and sold it, and over thousands of years we got fed up of saying "okay you can't make bread padded with sawdust", "you can't sell arsenic wallpaper", "you can't sell deathly metabolism boosters as diet pills", "you can't sell public buildings that are a death trap", "you can't say your product was approved by The King if it wasn't" and flipped to say "you can only sell medicine and treatments which are generally recognised as safe, or you prove case-by-case that they are safe", "your advertising must tell the truth". And that's better.
We humans also used to be naked by default, and over time we've switched to being clothed-by-default. Occasionally it results in people having to cover their genitals when they'd rather not, but mostly it's resulted in body protection from sun, heat, cold, brick, concrete, metal, and reduced amount of poop covering communal seats and other surfaces, the ability to carry stuff in pockets and is generally a big win.
Frankly, "here is an edge case hah gotcha" is geek fun for arguing, but a shitty way to decide what to do. If a sorting algorithm sometimes doesn't sort things it's a dealbreaker, but a restaurant which keeps separate raw and cooked fridges, separate chopping boards and knives, and asks the staff to wash their hands with soap before food preparation might have an edge case where they employ someone foreign and dyslexic who cannot read the English sign about hand washing and because of that some customer gets food poisoning is a far far better situation than saying "hah I imagined an edge case therefore let's not have any public health laws, let's just make it a free for all".